1. Field of the Invention
The invention concerns a device for making or breaking a light path through a fiber optic circuit.
2. The Prior Art
Fiber optic circuits are recognized as desirable substitutes for the electrical type in areas where fire and explosion hazards exist. Consequently, fiber optic circuits have found utility in petrochemical plants, grain elevators, munitions plants, refineries, mines, ships and aircraft. One of the challenges in substituting fiber optic for electrical wire systems is the design of non-electrical switch mechanisms to regulate transmission of light.
Some electrical switches operate using the principles of magnetism. For instance, there are commercially available liquid level controllers sold by a number of companies including Thomas Products Ltd. and Transamerica DeLaval Inc. These devices comprise a magnetic fitted float pivotally attached to a housing containing an iron reed switch. The float is suspended in the fluid to be monitored. A rise in fluid level causes the float also to rise and eventually to magnetically influence the reed switch to activate an electrical circuit.
Often the fluids to be monitored contain organic solvent. Electrical connections, which are only partially avoided in the afore-described devices, have potential for igniting the solvent. Water based fluids, although non-flammable, can cause short-circuiting within the electrical connections. Fiber optic monitors would therefore be useful for such applications. It would also be desirable to generally utilize the principle of magnetism in the design of a fiber optic light regulator.
Consequently, it is an object of this invention to provide a device activated by a magnet for regulating light transmissions through an optical fiber.
A further object of this invention is to monitor a liquid level or liquid flow rate with a non-electrical switch based upon light transmission through an optical fiber.
A further object of this invention is to provide an optical fiber switch controlling machinery movement wherein a magnet activates a change in light transmission through the fiber optic.
These and other objects of this invention will become more apparent upon consideration of the following detailed description taken in conjunction with the accompanying drawings.